The present invention relates to a rack and pinion steering gear, and more particularly, to a rack and pinion steering gear with a unitized yoke assembly.
A known rack and pinion steering gear includes a pinion gear that is rotatably mounted in a housing and is connected with a steering wheel of a vehicle. A rack bar extends through the housing and has opposite end portions connected with steerable vehicle wheels. Gear teeth formed on the rack bar are disposed in meshing engagement with gear teeth on the pinion gear. A yoke assembly is disposed in the housing to at least partially support and guide movement of the rack bar relative to the housing. The support provided by the yoke assembly helps to ensure proper lash between the gear teeth of the rack bar and the gear teeth of the pinion gear.
Known yoke assemblies include a yoke having an arcuate first surface for contacting and supporting the rack bar. A helical compression spring contacts a second surface of the yoke for biasing the yoke against the rack bar. The yoke is held in a yoke bore of the rack and pinion steering gear housing by a plug. The plug has external threads that screw into internal threads located in a yoke bore of the housing.
To install the known yoke assembly in the rack and pinion steering gear housing, the yoke is placed into the yoke bore such that the first surface of the yoke contacts the rack bar. The spring is inserted into a bore on a second surface of the yoke. The yoke plug is screwed a short distance into the yoke bore. Next, the rack and pinion steering gear is placed on a yoke set machine. The yoke set machine screws the plug into the yoke bore to set a proper clearance between the yoke and the plug. To set the proper clearance, the yoke set machine places known loads on the rack bar and based upon deflection of the rack bar correlates a clearance between the yoke and the plug. When a proper clearance exists between the yoke and the plug, the rack and pinion steering gear is removed from the yoke set machine and an adhesive is applied to lock the plug to the housing. The adhesive ensures that the clearance between the yoke and the plug is not later changed.
The present invention is a rack and pinion steering gear. The rack and pinion steering gear comprises a housing having a longitudinally extending passage. A yoke bore extends perpendicular to the longitudinally extending passage and connects with the longitudinally extending passage within the housing. A pinion gear is rotatably mounted in the housing. The pinion gear has teeth. A rack bar extends through the longitudinally extending passage of the housing and is movable relative to the pinion gear. The rack bar has teeth in meshing engagement with the teeth of the pinion gear. A yoke assembly is located in the yoke bore of the housing for at least partially supporting and guiding movement of the rack bar relative to the pinion gear. The yoke assembly includes a yoke, a yoke plug, and an elastomeric spring. The yoke is axially spaced from the yoke plug by the elastomeric spring. The elastomeric spring is secured to the yoke and to the yoke plug so that the yoke, the elastomeric spring, and the yoke plug form a unitized assembly.